Towards circular plastics within planetary boundaries

Abstract

The rapid growth of plastics production exacerbated the triple planetary crisis of habitat loss, plastic pollution and greenhouse gas (GHG) emissions. Circular strategies have been proposed for plastics to achieve net-zero GHG emissions. However, the implications of such circular strategies on absolute sustainability have not been examined on a planetary scale. This study links a bottom-up model covering both the production and end-of-life treatment of 90% of global plastics to the planetary boundaries framework. Here we show that even a circular, climate-optimal plastics industry combining current recycling technologies with biomass utilization transgresses sustainability thresholds by up to four times. However, improving recycling technologies and recycling rates up to at least 75% in combination with biomass and CO2 utilization in plastics production can lead to a scenario in which plastics comply with their assigned safe operating space in 2030. Although being the key to sustainability and in improving the unquantified effect of novel entities on the biosphere, even enhanced recycling cannot cope with the growth in plastics demand predicted until 2050. Therefore, achieving absolute sustainability of plastics requires a fundamental change in our methods of both producing and using plastics.

Upcycling Polyolefin Blends into High-Performance Materials by Exploiting Azidotriazine Chemistry Using Reactive Extrusion

“…Although the commercial demand for plastics has doubled in the past 20 years, 1,2 the current plastics industry is far from being sustainable. 3−5 Of the 391 Mt of plastics produced worldwide in 2021, only 8.3% was derived from postconsumer recyclates.…”

“…Although the commercial demand for plastics has doubled in the past 20 years, , the current plastics industry is far from being sustainable. − Of the 391 Mt of plastics produced worldwide in 2021, only 8.3% was derived from postconsumer recyclates . There is hence an urgent need to develop a circular economy to curb the accumulation of plastic waste throughout the earth’s ecosystems. ,,, Among the established and emerging strategies for revalorizing plastic waste, ,− mechanical recycling is an appealing approach in terms of time, economic cost, and environmental impact. ,− Its main drawback is that it commonly yields materials with inferior mechanical properties compared to virgin materials, which is largely due to chain degradation during reprocessing and contamination by incompatible polymers. ,, Polyethylene (PE) and polypropylene (PP), which together constitute approximately half of the world’s polymer production, lose approximately 95% of their value at the end of their life with current recycling technology .…”

Chemical Recycling of Commercial Poly(l-lactic acid) to l-Lactide Using a High-Performance Sn(II)/Alcohol Catalyst System

“…Chemical recycling to monomer (CRM) is a powerful tool in efforts to circularize the plastic economy. , Indeed, recent systemic analyses of the high greenhouse gas emissions for future plastics systems all highlight the imperative for major increases in recycling to preserve both the waste plastic embedded energy and material value. − So far, chemical recycling to monomer is most often demonstrated using newly invented polymers, with great potential as future circular materials, but not currently found in existing waste streams. − It is equivalently important to develop chemical recycling to true monomer using currently used commercial plastics. Poly­( l -lactic acid) (PLLA) is one of the largest commercial, sustainable polymers, produced at 200,000–300,000 tonne/annum, and sourced from crops, via fermentation of starches to l -lactic acid. , The lactic acid undergoes polycondensation to form oligoesters, which are thermally decomposed to form the cyclic dimer l -lactide ( l -LA) .…”

The Relevance of Life Cycle Assessment Tools in the Development of Emerging Decarbonization Technologies

“…The current trend tries to include the assessment of the absolute sustainability level of decarbonization pathways for the chemical industry, which has been appointed as a key strategy to guide development as well as policy-making . Several studies that apply the PB framework for decision-making have been published in recent years. − Galán-Martin et al applied PB-LCA to evaluate the transition of the petrochemical industry to renewable carbon-based, highlighting the opportunities to incorporate PBs in the decision-making when assessing large-scale decarbonization routes. D’Angelo et al assessed the absolute sustainability performance of low-carbon ammonia synthesis routes from the PB-LCA perspective.…”